A fluid actuated rotary chuck assembly of the type with which the present invention is concerned is typically used in a production machine tool to secure and rotate a workpiece while a series of machining operations, such as turning, boring, reaming and tapping, are performed on the workpiece to form an article of manufacture. In the performance of such machining operations it is essential that sufficient clamping pressure be applied to grip and hold the rotating workpiece against the reactive force of an engaging tool. The clamping or chucking pressure required is generally determined by the physical characteristics of the workpiece and the operations that are to be performed upon it. Thus, for example, the clamping pressure necessary to properly secure a workpiece when a turning operation is to be performed on the workpiece will be substantially greater than the clamping force required to hold the same workpiece during a grinding or finishing operation. Further, the clamping force which may be applied to a solid workpiece will be substantially greater than that which may be applied to a hollow or tubular workpiece used in the manufacture of a fragile article. However, in each instance sufficient holding force must be applied to the workpiece to resist the reactive force of a tool without causing distortion of either the workpiece or the article of manufacture produced by the machining process. Each time a machine setup is changed to satisfy the particular requirements of another production run proper consideration must be given to chucking pressure requirements and an appropriate chuck adjustment must be made, when necessary. The present invention is concerned with the aforesaid problems.
It is the general aim of the present invention to provide an improved adjustable, air actuated chuck assembly which enables increased clamping pressure without increase in pressure at the air supply source and which offers a wide range of chucking pressures. It is a further aim of the invention to provide an improved air actuated chuck assembly operated by an adjustable regulating device to enable a machine operator of ordinary skill to rapidly and accurately adjust chucking pressure to satisfy the chucking pressure requirements of a particular job whereby job setup time may be minimized.